Corporate-action and delisting lifecycle replay

AlphaForge now replays point-in-time splits, cash dividends, and metadata-confirmed delistings inside the event-driven backtester. This is engineering evidence, not a claim of complete historical coverage or investment performance. No return data was opened and no research hypothesis was spent.

Enforced behavior

• Every split and cash dividend retains its ex date and source availability timestamp.
• An event published after its ex boundary fails closed; the engine will not rewrite an earlier holding with information that was unavailable then.
• Splits convert held shares, average entry prices, and pre-ex queued quantities before the ex-date fill. A price-discontinuity guard rejects inconsistent split records.
• Cash dividends accrue against the signed position entering the ex date: longs receive and shorts pay. The current schema lacks a payable date, so this is explicitly booked as an ex-date receivable or payable.
• Applied transformations and cashflows persist in corporate_actions.parquet with each backtest.
• A terminal price history is liquidated only when SCD2 instrument metadata supplies a qualifying delisted_ts. If metadata still says active, the run halts instead of inventing an exit.

Defects closed

The prior engine ignored dividend rows already present in the point-in-time lake. It also treated any terminal price history as a delisting and sold at the last close, even when lifecycle metadata said the instrument was active. Finally, a split converted an existing position but did not rescale a pre-ex order when the book was flat, allowing a reverse split to multiply intended exposure. Focused regressions now pin all three cases.

Deliberate boundary

The platform does not yet model payable-date settlement, withholding tax, fractional-share cash-in-lieu, mergers, tender consideration, spin-offs, rights, symbol changes, bankruptcy recoveries, delisting auctions, vendor correction histories, or live broker reconciliation. Complex same-boundary split/dividend combinations fail closed when the holding is exposed because the current lake does not encode deliverable-basis ordering.

The machine-readable contract is available at /glassbox/corporate_action_contract.json.